Middle English poetry relies on repetition to create its rhythms and artfulness. Metre and rhyme-schemes are in themselves patterns of repetition, patterns of alternate stress and of repeated rhyme-sounds. Repetitions can be consciously planned by poets, built into their poetry even as they juggle the demands of meaning, metre and rhyme. Or they can be found in poems by readers who can find meaning and coherence in something a poet has not consciously planned. As well as the repetition of words and phrases, grammatical structures can be repeated (i.e. the same syntactical pattern repeated with different words in each instance).
Grammatical words (also called function words, such as but, she, would) often get repeated. Sometimes these repetitions are unavoidable – the poet just couldn’t construct his meaning without them. At times grammar words are redundant in terms of the meaning of the sentence (i.e. we would still understand the sentence if the repeated grammar word were left out), but are necessary for the metre or to create a pattern or parallel. So, if you notice a repetition of a grammar word, check whether it is needed for the metre, to create the necessary rhythmic alternation between weakly and strongly stressed words, or needed to create a pattern. It may be strictly pleonastic (that is, using more words than are strictly necessary for the meaning), but nevertheless required at the level of form.
Here’s an example from Book IV of Troilus and Criseyde, from the scene in which Troilus expresses his sorrow after parliament decides to exchange Criseyde for Antenor. (There’s a translation at the foot of this post, as the syntax is quite tricky to follow.)
I shal, whyl I may dure
On lyve in torment and in cruel peyne,
This infortune or this disaventure,
Allone as I was born, y-wis, compleyne;
Ne never wil I seen it shyne or reyne;
But ende I wil, as Edippe, in derknesse
My sorwful lyf, and dyen in distresse.
It might be tempting to comment on the repetition of the pronoun ‘I’ as an example of Troilus’s self-absorption. But given that he is on his own here, expressing his own feelings, perhaps we should allow him these sorts of repetitions without too much scorn. The pleonastic repetitions of in (in line 2) and this (in line 3) allow Chaucer to manage the demands of his metre and to create balanced phrasing. The stanza makes use of a good deal of parallelism, repetition and variation. We could read this as over-emphasis, as too-much artifice, or we could see it as the exquisitely versified imagining of a prince’s lament. Try not to evaluate a character’s language simply as speech, but remember the paradox that this is poetry pretending to be impromptu utterance.
Repetition can thus be a part of style as well as content. We might assume that repetition is used just to emphasise particular ideas, to reiterate a point, to signal emotions. But it is also a rhetorical figure, a planned pattern put into words for a particular effect, recognizable as such by other readers. Chaucer and his readers would have known the rhetorical figure conduplicatio (defined as the repetition of words or phrases) from discussions of rhetorical figures or schemes in Latin poetry. They would also have known the figure adnominatio (the repetition of a word in a different form, see a Lydgate example here). So when Chaucer repeats words (especially content words consciously repeated), he is writing artfully with rhetorical figures.
There are various more specialised types of repetition. Students often point out anaphora (perhaps because it combines a scheme which is relatively easy to spot with a name that we can all remember how to spell!). Anaphora is a rhetorical scheme in which the same word is repeated at the beginning of successive clauses, sentences or lines. It’s particularly noticeable when the repeated words line up one above another at the start of successive lines (for a good example, see Troilus Book II.344ff).
Be careful, though, not to impose a label that fits linguistically on a feature which is there for a different reason. Chaucer often has successive lines beginning with ‘and’, but this is more a consequence of polysyndeton. He sometimes has successive lines beginning with ‘O’, but these are vocative phrases which signal apostrophe or exclamatio. If you are labelling repetition as a rhetorical figure, choose the figure that best fits the reason why your poet might have repeated these words.
[I will, utterly alone, lament this misfortune or this misadventure, for as long as I can survive, living in torment and cruel pain; I will never see sunshine or rain, but I will end my sorrowful life, like Oedipus, in darkness, and die in distress.]
Amanda Holton, The Sources of Chaucer’s Poetics (Ashgate, 2008), pp. 96–103